Digital-to-analog converters (DACs), analog-to-digital converters (ADCs), or low-dropout regulators (LDOs) generally require at least one stable reference voltage. The reference voltage needs to be steadily regenerated every time when the power turns on, and such reference voltage needs to be kept away from process, temperature or electrical variations, etc.
A bandgap voltage reference circuit may be used to provide such a reference voltage. Therefore, bandgap voltage reference circuits play an important role in many very large scale integrated (VLSI) circuit systems, and determine the overall stability and precision of the systems. A common bandgap voltage reference circuit usually adopts a two-stage amplifying circuit framework and is used with a Miller capacitor for frequency compensation. However, the speed for starting such bandgap voltage reference circuit is usually slower. Besides, the driving ability of the common bandgap voltage reference circuit is also insufficient, which limits its application as the bandgap voltage reference circuit. Therefore, how to increase the starting speed and facilitate the driving ability of the bandgap voltage reference circuit is an issue for the artisans of the field to work on.